Commercial Hot Water Control Systems

ABSTRACT

A commercial hot water system includes a hot water source, and a hot water delivery line connected between the hot water source and at least one plumbing fixture. A pump, enables circulation of hot water to and from the fixtures. A controller provides for turning on the pump in conjunction with an external signal, and a detector, preferably a temperature sensor, in conjunction with the controller, is effective in stopping the pump to prevent heated water from being circulated.

This application is a continuation-in-part of U.S. Patent applicationSer. No. 12/641,236, filed Dec. 17, 2009, which is hereby incorporatedby reference herein in its entirety.

The present invention is generally directed to plumbing systems and moreparticularly directed to commercial plumbing systems with energy savingrecirculation of water.

In large buildings, such as, for example, apartment buildings, hotels,motels, and other commercial buildings, the boiler, or hot water supply,is disposed remotely to the point of use of hot water. Accordingly, ifthe water in the piping system has cooled, a user may have to run thewater for an extended period of time in order to get hot water to afixture.

In this case, water is wasted because the cooled water in the pipes istypically discharged into a drain during a period of time waiting forthe arrival of hot water. Energy is also wasted because the dischargedwater was heated previously by the boiler.

This problem of both water waste and inconvenience has been solved byproviding hot water recirculation systems which are installed incommercial buildings. Continuous circulation of hot water around theloop is quickly available at various points of use throughout thebuilding. Most often, an electrically driven pump is installed at an endof a return line which draws hot water from the supply side of theboiler and returns it to the cold water inlet of the hot water supply.

This type of system enables quick access to hot water and, in fact,saves water; however, it is wasteful from an energy conservation pointof view.

Even when insulated, recirculation pipes have a high heat loss.Accordingly, the heat loss from a continuously operating recirculationsystem can be quite high.

In order to conserve energy, systems may be configured to turn off therecirculation pump at specific times. This may be affected through atime clock which operates recirculation pump during the day and turnsthe pipe off at night.

While this system will reduce the heat loss at night, it has a severedrawback because recirculation is actually needed most during theevening. That is, during the day in an apartment building orhotel/motel, people will often use hot water at a number of fixturesthroughout the building. This water draw keeps water in the distributionsystem thereby providing hot water quickly.

However, at night, very little hot water use occurs. When a person useshot water at night, without operation of the recirculation pump a longtime may be necessary for hot water to arrive at a remote fixture.

Accordingly, a system is desirable which enables the continuous, orsporadic, use of recirculation to maximize efficiency of this system,depending on the users' requirements. The present invention solves thatproblem.

SUMMARY OF THE INVENTION

A hot water delivery system in accordance with the present inventiongenerally includes a boiler having a storage tank interconnectedtherewith and hot water delivery lines connected between the storagetank and at least one plumbing fixture. A cold water delivery line isprovided and connected between the plumbing fixture and a cold watersource and the boiler for delivering cold water thereto.

A pump is provided which is interconnected between the boiler and thestorage tank, for circulation of the water from the storage tank to thefixture and return to the storage tank. A controller causes the pump tocirculate water.

A temperature sensor, connected to the control system, is provided forcausing the controller to stop the pump to prevent heated water frombeing circulated; a timer may be connected to the controller to turn onthe pump. Alternatively, the pump may be turned on by the controllerusing any of various ways, such as through use of a switch or button, orautomatically by use of, for example, a flow detector installed in thehot water line, or opening a hot water faucet.

BRIEF DESCRIPTION OF THE DRAWINGS

The advantages and features of the present invention will appear fromthe following description when considered in conjunction with theaccompanying drawing, in which:

FIG. 1 is a flow diagram of a plumbing system 10 in accordance with thepresent invention for a commercial establishment, such as an apartmentbuilding, generally showing a boiler and conduits, in communication withat least one plumbing fixture, along with a pump, flow switch,controller, and timer.

DETAILED DESCRIPTION OF THE DRAWINGS

Referring to FIG. 1, there is shown a hot water recovery system 10 for abuilding 14 which generally includes a boiler 18, connected to a storagetank 22, and supplied by a feed line 24. A hot water delivery line 28connecting the tank 22 with a plurality of plumbing fixtures 32 that aredispersed throughout the building 14. Also provided is a cold waterdelivery line 36 interconnecting the fixtures 32 with a cold water line36 which is also interconnected with the boiler 18.

A pump 46 is connected between the boiler 18 and storage tank 22 forcirculation of water to and from the fixture 32 in order to provide“instant” hot water at the fixtures and a controller 50 provides forswitching electrical current from an outlet 52 to the pump 46 in orderto cause the pump 46 to circulate water from the storage tank 22 to thefixture 32.

A detector, such as a temperature sensor, sound detection sensor, orflow detector, 56 may be disposed in a line 54 interconnecting the pump46 with the storage tank 22 and causes the controller 50 to stop thepump 46 to prevent heated water from being circulated. Preferably thedetector 56 is a temperature sensor, which may be a thermistor type ofdetector strapped to the outside of the line 54.

If the detector is a temperature sensor 56 is preferably configured foruse with the controller for detecting a temperature increase, orgradient in the line over a relatively short preset period of time, forexample, over a time value from about 5 seconds to about 15 minutes. Thetemperature increase may also be preset to detect a change during thepreset time period of, for example, one or two degrees or more, and inresponse thereto causing the control system 52 to stop the pump 46.Thus, no matter what the actual temperature of the water in the line 54is, an increase of, for example, one or two degrees will cause the pump46 to stop. The pump may be turned on by the controller using any ofvarious ways, such as through use of a switch or button, a flow sensoror temperature drop, sound detection sensor, or opening a hot waterfitting. Preferably, a timer 64 may be incorporated into the controller50 for causing the controller 50 to turn on the pump 46 at preset times.Preferably, the pump is stopped by the controller 50 receivinginformation through the temperature sensor 56.

Although the timer 64 is shown incorporated into the controller 50 ifpresent it may be disposed anywhere in the system.

Although there has been hereinabove described a specific commercial hotwater system in accordance with the present invention for the purpose ofillustrating the manner in which the invention may be used to advantage,it should be appreciated that the invention is not limited thereto. Thatis, the present invention may suitably comprise, consist of, or consistessentially of the recited elements. Further, the inventionillustratively disclosed herein suitably may be practiced in the absenceof any element which is not specifically disclosed herein. Accordingly,any and all modifications, variations or equivalent arrangements whichmay occur to those skilled in the art, should be considered to be withinthe scope of the present invention as defined in the appended claims.

What is claimed is:
 1. A hot water recovery system comprising: a) a feedline supplying cold water to a boiler; b) a hot water delivery linecirculating hot water directly or indirectly from said boiler to one ormore plumbing fixture dispersed throughout a building, and returningunused water; c) a pump circulating water in a closed loop directly orindirectly from said boiler to said plumbing fixture and returningunused water from said fixture; d) a controller, for turning on the pumpin accordance with an external signal, and turning off the pump inaccordance with information received from a detector, connected theretoand disposed in a water line, indicating a decreased use of hot water.2. The hot water recovery system of claim 1 wherein said detector is atemperature sensor, and said temperature sensor and controller areconfigured to detect a selected temperature increase and in responsethereto cause the controller to turn off the pump to prevent heatedwater from being circulated.
 3. The hot water recovery system of claim 1wherein said temperature increase is from about one to about two degreesF.
 4. The hot water recovery system of claim 1 comprising a hot waterstorage tank fluidly connected between said boiler and said at least oneplumbing fixture.
 5. The hot water system of claim 2 wherein a timer,connected to said controller, causes said controller to turn on saidpump at a present time.
 6. A method of controlling the circulation ofhot water in a building comprising: a) receiving cold water from a coldwater source through a feed line; b) heating said hot water; c)circulating said hot water through a hot water line in a closed loop toand from one or more plumbing fixture using a pump; d) turning the pumpon or off using a controller according to hot water demand; wherein saidcontroller is connected to a detector disposed in said hot water lineand turns off said pump when it receives a first signal from saiddetector indicating a lack of hot water demand, said pump is turned onwhen said controller receives a second signal indicating a demand forhot water.
 7. The method of claim 6 wherein said heating step comprisesdirecting water into a boiler.
 8. The method of claim 6 wherein saidsecond signal is generated by a timer connected to said controller. 9.The method of claim 6 wherein said first signal is received from adetector disposed in said hot water line.
 10. The method of claim 7wherein said detector is a temperature sensor and said controller shutsdown the pump when a temperature increase in said hot water line isdetected.
 11. The method of claim 10 wherein said temperature increaseis from about 1 to about 2 degrees F.
 12. The method of claim 8 whereinsaid first signal is received from a detector disposed in said hot waterline.
 13. The method of claim 7 wherein said detector is a temperaturesensor and said controller shuts down the pump when a temperatureincrease in said hot water line is detected.
 14. The method of claim 12wherein said temperature increase is from about 1 to about 2 degrees F.